Why is understanding the relationship of testosterone to cardiovascular risk so important? / 亚洲男科学杂志(英文版)

Epidemiological studies hint at a beneficial influence of endogenous circulating testosterone (T), or its metabolite dihydrotestosterone (DHT), such that men with lower concentrations of T or DHT appear to have poorer health outcomes including frailty, diabetes, cardiovascular disease, and mortality. Small interventional studies of T have shown favorable effects on surrogate outcome measures, but a large randomized controlled trial (RCT) with the prespecified outcome of cardiovascular events has not been performed and would be logistically demanding. In the absence of such a definitive RCT, there is a controversy about the cardiovascular risks of T-therapy fuelled by contradictory findings from retrospective analyses of insurance databases of men prescribed T. The US Testosterone Trials (T-Trials) are the largest published RCTs of T-therapy in older men with symptoms or signs of hypogonadism and circulating T <9.54 nmol l−1 at baseline. The T-Trials showed a modest benefit of T-therapy over a 12-month period on sexual function, a significant benefit in bone density and for anemia and neutral effect on cognition. The T-Trials cardiovascular sub-study was designed to determine the effects of T in these older men, and there was a statistically significant difference in the increase in noncalcified plaque volume in the T-treated group compared to placebo, but it is difficult to interpret these results due to differences in baseline coronary plaque burden (>50% difference) between the treatment and placebo arms of the subset involved. Therefore, there continues to be ongoing uncertainty over the effect of T-therapy on the cardiovascular system in men.

Endogenous testosterone and mortality risk / 亚洲男科学杂志(英文版)

In men, obesity and metabolic complications are associated with lower serum testosterone (T) and dihydrotestosterone (DHT) and an increased risk of, and mortality from, multiple chronic diseases in addition to cardiovascular disease (CVD). The causal interrelationships between these factors remain a matter of debate. In men with untreated congenital and lifelong forms of hypogonadotropic hypogonadism, there appears to be no increased risk. Men with Klinefelter's syndrome have an increased risk of various types of cancers, as well as CVD, which persist despite T therapy. In the absence of pathology of the hypothalamic-pituitary-gonadal axis, the effect of modest reductions in serum T in aging men is unclear. The prevalence of low serum T concentrations is high in men with cancer, renal disease, and respiratory disease and is likely to be an indicator of severity of systemic disease, not hypogonadism. Some population-based studies have found low serum T to be associated with a higher risk of deaths attributed to cancer, renal disease, and respiratory disease, while others have not. Although a meta-analysis of longitudinal studies has shown an association between low serum T and all-cause mortality, marked heterogeneity between studies limited a firm conclusion. Therefore, while a decrease in T particularly occurring later in life may be associated with an increase in all-cause and specific types of mortality in men, the differential effects, if any, of T and other sex steroids as compared to health and lifestyle factors are unknown at the current time.

Visceral adiposity index and triglyceride/high-density lipoprotein cholesterol ratio in hypogonadism

ABSTRACT Background Cardiometabolic risk is high in patients with hypogonadism. Visceral adiposity index (VAI) and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio are the practical markers of atherosclerosis and insulin resistance and independent predictors of cardiaovascular risk. To date, no study has evaluated VAI levels and TG/HDL-C ratio in hypogonadism. Subjects and methods A total of 112 patients with congenital hypogonadotrophic hypogonadism (CHH) (mean age, 21.7 ± 2.06 years) and 124 healthy subjects (mean age, 21.5 ± 1.27 years) were enrolled. The demographic parameters, VAI, TG/HDL-C ratio, asymmetric dimethylarginine (ADMA), high-sensitivity C-reactive protein (hs-CRP), and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured for all participants. Results The patients had higher total cholesterol (p = 0.04), waist circumference, triglycerides, insulin, and HOMA-IR levels (p = 0.001 for all) than the healthy subjects. VAI and ADMA and TG/HDL-C levels were also higher in patients than in healthy subjects (p < 0.001 for all). VAI was weakly correlated with ADMA (r = 0.27, p = 0.015), HOMA-IR (r = 0.22, p = 0.006), hs-CRP (r = 0.19, p = 0.04), and total testosterone (r = −0.21, p = 0.009) levels, whereas TG/HDL-C ratio was weakly correlated weakly with ADMA (r = 0.30, p = 0.003), HOMA-IR (r = 0.22, p = 0.006), and total testosterone (r = −0.16, p = 0.03) levels. Neither VAI nor TG/HDL-C ratio determined ADMA, HOMA-IR, and hs-CRP levels. Conclusions The results of this study demonstrate that patients with hypogonadism have elevated VAI and TG/HDL-C ratio. These values are significantly correlated with the surrogate markers of endothelial dysfunction, inflammation, and insulin resistance. However, the predictive roles of VAI and TG/HDL-C ratio are not significant. Prospective follow-up studies are warranted to clarify the role of VAI and TG/HDL-C ratio in predicting cardiometabolic risk in patients with hypogonadism.

Congenital leptin deficiency: diagnosis and effects of leptin replacement therapy / Deficiência congênita de leptina: diagnóstico e efeitos da terapia de reposição

To describe our 10-year experience in treating leptin-deficient humans. Three adults and one boy presented with childhood-onset morbid obesity, hypogonadism and family history of obesity and early death. Serum leptin was inappropriately low. A recessive C105T leptin gene mutation was identified. Metabolic and endocrine assessments were conducted, before and while on and off leptin. The adults' body mass index decreased from 51.2 ± 2.5 to 29.5 ± 2.8 kg/m². Serum lipids normalized, insulin resistance decreased, and one of the initially diabetic females became normoglycemic. Hypogonadotropic hypogonadism was reversed, and other changes were observed in the adrenal, sympathetic, somatotropic and thyroid functions. Leptin replacement therapy reverses endocrine and metabolic alterations associated with leptin deficiency. Some of these results may be extrapolated to other diseases.

Descrever nossa experiência de 10 anos tratando pacientes deficientes em leptina. Três adultos e um menino apresentaram obesidade mórbida com início na infância, hipogonadismo e história familiar de obesidade e morte precoce. A leptina sérica era inapropriadamente baixa. A mutação recessiva C105T no gene da leptina foi identificada. Avaliações metabólicas e endócrinas foram realizadas antes e durante o tratamento. O índice de massa corporal dos adultos baixou de 51,2 ± 2,5 para 29,5 ± 2,8 kg/m². Houve normalização dos lipídios séricos, a resistência insulínica diminuiu e a paciente que era diabética se tornou normoglicêmica. O hipogonadismo hipogonadotrópico foi revertido e outras alterações foram observadas nas funções adrenal, simpática, somatotrópica e tireoidiana. A reposição de leptina reverte as alterações endócrinas e metabólicas associadas com a deficiência de leptina. Alguns desses resultados podem ser extrapolados para outras doenças.

Apoptose, proliferação e histomorfometria do baço de ratas adultas com hipofunção tireoidiana e ovariana / Apoptosis, proliferation and spleen histomorphometry of adult female rats with thyroid and ovarian hypofunction

Apoptose, proliferação e histomorfometria do baço foram investigados em ratas Wistar adultas ovariectomizadas e não-ovariectomizadas, mantidas em hipotireoidismo induzido pela administração diária de propiltiouracil (PTU) por 120 dias. Dois grupos eutireóideos ovariectomizados e não-ovariectomizados serviram como controle. Foi colhido o plasma para dosagem de T4 livre e o baço para análise da histomorfometria, do índice apoptótico e da expressão imunohistoquímica de caspase 3 e CDC47. Valores de T4 livre foram menores nas ratas tratadas com PTU (p < 0,05). Nos grupos hipotireóideos houve redução do peso do baço, do número e do tamanho dos folículos linfóides e aumento do índice apoptótico e da expressão de caspase 3 (p < 0,05). Porém, o baço de ratas hipotireóideas ovariectomizadas apresentou aumento menos acentuado do índice apoptótico e da expressão de caspase 3 do que o baço de ratas hipotireóideas não-ovariectomizadas (p < 0,05). O grupo eutireóideo ovariectomizado apresentou hiperplasia da polpa branca em relação ao grupo eutireóideo não-ovariectomizado. Não houve diferença na expressão de CDC47 entre os grupos. Conclui-se que a hipofunção tireoidiana e gonadal apresentam efeitos distintos no baço e que na associação hipotireoidismo-hipogonadismo há aumento menos acentuado do índice apoptótico e da expressão de caspase-3 esplênica do que no hipotireoidismo isolado.

Apoptosis, proliferation and histomorphometry of spleen were investigated in ovariectomized and non-ovariectomized adult Wistar rats maintained in hypothyroidism induced by daily administration of propylthiouracil (PTU) during 120 days. Two groups ovariectomized euthyroid and non-ovariectomized euthyroid were used as controls. Plasma was collected for free T4 dosage and the spleen for histomorphometry analysis, apoptosis index and the immunohistochemistry expression of caspase 3 and CDC47. Values of free T4 were lower in rats treated with PTU (p<0.05). In the hypothyroid groups there was some decrease in the spleen weight as well as the number and size of lymphoid follicles and there was some increase in the apoptotic index and the caspase 3 expression (p<0.05). However, the increase in the apoptosis index and the expression of caspase 3 in ovariectomized hypothyroid rats spleen was less accentuated than non-ovariectomized hypothyroid ones (p<0.05). The ovariectomized euthyroid group presented white pulp hyperplasia in comparison to the non-ovariectomized euthyroid group. There was no difference in the CDC47 expression between groups. It was concluded that the thyroid and ovarian hypofunction have distinct effects on the spleen and that in the hypothyroidism-hypogonadism association, the increase in the apoptosis index and in the expression of splenic caspase 3 is not as much as in isolated hypothyroidism.

Resposta da paratireóide de ratas às variações do cálcio e fósforo plasmáticos no hipertireoidismo e hipogonadismo / Response of parathyroid to the plasmatic of calcium and phosphorus variations in hyperthyroidism and hypogonadism in the rat

Foram estudadas 84 paratireóides de ratas Wistar com cinco meses de idade, castradas ou não, e mantidas em hipertireoidismo por períodos de 30, 60 e 90 dias. Dois grupos eutireóideos, um castrado e o outro não, foram mantidos nas mesmas condições e serviram de controle. Ao final de cada período, foram colhidos o plasma, para determinação da concentração de T4 livre, o cálcio e o fósforo e as paratireóides, para análise morfológica e determinação da porcentagem de núcleo, citoplasma e estroma. Aos 90 dias houve reversão da hipocalcemia observada aos 60 dias nos animais eutireóideos castrados e não castrados, graças à hipertrofia da paratireóide. O mesmo não ocorreu com os grupos hipertireóideos que apresentaram hipocalcemia e hiperfosfatemia progressivas e não compensadas até os 90 dias. Na castração há pronta reversão da hipocalcemia em resposta ao aumento da atividade funcional da paratireóide. No estado hipertireóideo com gônadas funcionais, apesar da hipertrofia da paratireóide, não há retorno à isocalcemia e isofosfatemia. Na associação hipertireoidismo-castração, a paratireóide não responde satisfatoriamente à hipocalcemia e hiperfosfatemia intensas e progressivas.

A concomitant decrease in cortical and trabecular bone mass in isolated hypogonadotropic hypogonadism and gonadal dysgenesis

To assess the impact of hypogonadism on bone mineral density, we performed a cross-sectional study of 70 amenorrheic women, comprising 22 cases of gonadal dysgenesis and 48 cases of isolated hypogonadotropic hypogonadism (IHH). Bone mineral density was measured by DEXA at four sites: the femur neck, Ward's triangle, trochanter, and lumbar spine (L2-4). The results were compared to those of a control group consisting of 60 age-matched, normal-cycling women. Bone mineral densities around age 20 were already significantly lower at all four sites in patients with IHH and gonadal dysgenesis when compared with controls, suggesting that these patients failed to achieve peak bone mass during pubertal development. In patients with IHH, the initial BMD around age 18-20 were significantly lower at all four sites and the decrease in bone density continued rapidly during the early twenties up to age 25, and then it slowed markedly thereafter. Bone biochemical marker, ICTP and osteocalcin were significantly negatively correlated with age and remained increased until age 40, which was reminiscent of menopausal bone loss pattern such as high bone turn-over in the early twenties, followed by slow bone loss in the late twenties. In patients with gonadal dysgenesis, bone biochemical marker, ICTP and osteocalcin were also significantly negative correlated with age and remained increased until age 40, but no significant changes in BMD were noted as a function of age, which may be attributed to the small sample size and slow bone loss. These findings suggest that the initiation of prompt and timely therapeutic intervention as early as possible in the menarchal period and throughout the remainder of life, particularly during the period associated with rapid bone loss.

Alteraçöes na densitometria óssea em pacientes com hipogonadismo hipergonadotrófico / Bone densitometry changes among patients with hypergonadotrophic hypogonadism

INTRODUÇÄO: A osteoporose e a osteopenia säo alteraçöes na densidade óssea (DO) associadas a situaçöes que cursam com hipoestrogenismo, näo só na pós menopausa mas também em casos de hipogonadismos hipergonadotróficos. OBJETIVOS: avaliar alteraçöes na DO de pacientes com hipogonadismo näo relacionado a climatério (Síndrome de Turner, Disgenesia Gonadal Pura, Falência Ovariana Precoce), e o efeito de Terapia de Reposiçäo Hormonal (TRH) na prevençäo ou reversäo de tais alteraçöes. PACIENTES E MÉTODOS: Nossa casuística constou de 14 pacientes atendidas no setor de Reproduçäo Humana do Hospital das Clínicas da Faculdade de Medicina de Ribeiräo Preto da Universidade de Säo Paulo. Dessas pacientes 6 apresentavam Síndrome de Tuner, 4 eram portadoras de Disgenesia Gonadal Pura e 4 tinham Falência Ovariana Precoce. O diagnóstico se baseou na história clínica, exame físico, dosagens hormonais e avaliaçäo genética com cariótipo. Todas foram submetidas à DO com o densitômetro de dupla radiaçäo Sophos L-XRA. RESULTADOS: Encontramos diminuiçäo na DO em pacientes de todos os grupos, näo havendo diferença significativa entre os três grupos. As pacientes que näo apresentaram alteraçöes na DO foram aquelas com menor intervalo de tempo entre início da sintomatologia de hipoestrogenismo e instituiçäo de TRH. Pacientes que permaneceram por mais de 3 anos sem TRH apresentaram alteraçöes na densidade óssea proporcional ao tempo de deprivaçäo hormonal. Também observamos que pacientes que entraram num processo de falência ovariana após os 20 anos de idade têm melhor prognóstico quanto à quantidade de massa óssea. CONCLUSÖES: Enfatizamos com esses dados a necessidade de TRH nessas pacientes, com finalidade de prevenir alteraçöes na densidade óssea conseqüentes ao hipoestrogenismo.